Biorefinery for upgrade and production increasing of biogas combined with effluent treatment

• Grant number: 22/16028-0
• Support Opportunities: Research Grants - Innovative Research in Small Business - PIPE
• Field of knowledge: Biological Sciences - Ecology - Applied Ecology
• Principal Investigator: Flávia Bottino
• Grantee: Flávia Bottino
• Company: Bottino Pesquisa e Desenvolvimento em Biotecnologia Inova Simples
• CNAE: Descontaminação e outros serviços de gestão de resíduos
• City: Araraquara
• Associated researchers: Paulo Vagner dos Santos
• Associated scholarship(s): 23/10928-2 - Using microalgae for treatment of waste derived from anaerobic digestion., BP.TT; 23/08587-2 - Microalgae used as biotechnological tool, BP.TT; 23/06211-5 - Biorefinery for upgrade and production increasing of biogas combined with effluent treatment, BP.PIPE

Abstract

Anaerobic Digestion (AD) is a biochemical process that converts organic matter into biogas. The biogas utilization mainly as fuel requires the CO2removal by physical and chemical processes, which are expensive energetically and financially (up to 45% of the total cost of the AD project). These processes do not allow the conversion and reuse of CO2 which is released into the atmosphere, contributing to the global warming. The use of microalgae which absorb CO2 from biogas is an alternative way of biogas upgrade and is considered sustainable when using AD effluent as a culture medium. Finally, the recirculation of the biomass generated in the process of biogas upgrading in the anaerobic digester closes a cyclical process of capture of clean energy. This proposal aims at the implementation of a biorefinery for the treatment of the effluent derived from AD (digestate), biogas upgrade and co-digestion of the algal biomass with the organic substrate. Different strains of microalgae will be cultivated in bovine effluent digestate and the strain that shows the high growth rate will be cultivated for the biogas upgrade tests. The generated biomass will be co-digested with bovine effluent in order to increase biogas production. The biogas upgrade will be carried out in a flat plate photobioreactor composed of a secondary absorption column to minimize CO2 toxicity to microalgae, as well as to control pH and oxygen diffusion resulting from photosynthesis. The results obtained in this phase of the project will allow inferences about the feasibility of scaling up the process which will minimize the emission of greenhouse gases in the AD process, generating materials with high added value (biomass rich in proteins, lipids and natural pigments) and with the potential to increase methane generation by up to 30%. The implementation of these biorefineries is feasible in industrialized areas with different types of organic effluents, rural properties and even city halls, promoting the reuse of waste through the production of biofuel using a sustainable process. In addition, they can reduce biogas upgrading costs by half and enable establishments to adhere to socio-environmental policies. (AU)